DIY : 100w Led Flashlight
You ve probably seen something like this.
I needed something that is bright, can be used on bicycle and also you can carry when you go exploring.
I made simmilar thing to DIY Perks portable sun but instead of using big CPU heatsink i used smaller one and whole body of flashlight to cool down LED.
Flashlight can work almost 1 hour on full brightness but i added potentiometer so i can dimm it and use it alot longer.
Battery that i used is 4S2P from old laptop batteries
Building
I used 8 18650 batteries, 100W LED and 150W boost converter.
For monitoring batteries i got cheap Li-ion buzzer alarm that shows me voltage of all 4 batteries.
Fan is running on 6-7v and instead of step down converter i used resistor.
I installed small thumbwheel potentiometer from old headphones to control the light intensity.
I almost never use flashlight on full brightness becouse its really bright.
LED lenses could be added but since i use this in close enviroment i didnt put one.
Its really nice to carry this in forest becouse you can see everything in front of yourself.
Switch is on the handle so i can turn it on and off really easy.
Battery
You can find cheap laptop batteries online or you can buy 18650s.
Good 18650 has about 2Ah capacity but they cost about 5€ per battery.
If you buy lot of laptop batteries you can get 2€ per battery and maybe even less.
When i tested batteries i used resistor across 18650 and i measured time.
First i soldered them together but later i got 8 holders and use that instead.
To charge them i made 4 cell balance charger from 4 usb charger and 4 TP4056 usb lithium charging boards.
Each battery charges with 0,5A of current so it takes about 4-5h to fully charge it.
Flashlight can be powered from any source from 10v to 30v that can deliver 100w.
I just need to unscrew 2 terminals that are going from battery to booster and connect any other source